Lidia Morawska

Bio: Lidia Morawska is an academic researcher from Queensland University of Technology. The author has contributed to research in topics: Particle number & Ultrafine particle. The author has an hindex of 100, co-authored 746 publications receiving 95412 citations. Previous affiliations of Lidia Morawska include University of Surrey & Jinan University.

State of Epidemiological Evidence for the Health Impacts of Ultrafine Particles

Abstract: There has been increasing interest in the effect of ultrafine particles (UFP) on human cardiovascular and respiratory health. The adverse health impacts due to particle exposure are currently attributed to the mass concentration or the chemical composition of particles smaller than 10 μm (PM10) or 2.5 μm (PM2.5) in diameter. However, it has been hypothesised that it is actually UFP (< 0.1 μm) measured in terms of number concentration, as opposed to mass concentration, that might be responsible for the observed health effects. This paper presents the results of a critical literature review aimed at analysing the current state of epidemiological evidence for the effects of UFP on human health. In summary, the array of epidemiological studies conducted thus far suggests that UFP exposure is associated with human mortality, and respiratory and cardiovascular morbidity. This holds true despite the considerable gaps in knowledge that remain, and despite the inconsistencies found between some studies, resulting from some deficiencies in the study designs. The limited number of epidemiological studies conducted thus far indicates that there are comparable health effects of fine and ultrafine particles, which appear to be independent of each other. Fine particles show more immediate effects whilst ultrafine particles show more delayed effects on mortality. However, at present the database is too limited (in terms of both number of studies and number of subjects) and geographically restricted, to allow clear conclusions on the mode of action and/or generalisation to other settings. Consequently, it is recommended that further, better-designed studies be initiated to improve the understanding of health impacts of UFP.

Hygroscopic and Volatile Properties of Ultrafine Particles in the Eucalypt Forests: Comparison with Chamber Experiments and the Role of Sulphates in New Particle Formation

Abstract: Simultaneous measurements of the volatile and hygroscopic properties of ultrafine particles were conducted in a Eucalypt forest in Tumbarumba, South-East Australia, in November 2006 These measurements were part of an intensive field campaign EUCAP 2006 (Eucalypt Forest Aerosols and Precursors) The particles exhibited a 2 step volatilisation with the first component starting to evaporate at temperatures above 50 degrees Celsius With the onset of evaporation of the first component the hygroscopic growth factor increased This indicated that the particle was composed of a less volatile, but more hygroscopic core, which was coated with a more volatile, but less hygroscopic, coating The fraction of the more hygroscopic component was proportional to the measured maximum SO2 concentration indicating the role of gaseous H2SO4 in new particle formation As the volatilisation temperature of the second more hygroscopic component was above that for H2SO4 it is likely that this component is partially or fully neutralised H2SO4 Comparison with pinene smog chamber experiments shows an excellent agreement with the first step volatilisation indicating its origin in the photooxidation of a monoterpene precursor

Ultrafine particle exposure and biomarkers of effect on small airways in children.

Abstract: The small size and large surface area of ultrafine particles (UFP) enhance their ability to deposit in the lung periphery and their reactivity. The Ultrafine Particles from Traffic Emissions and Children's Health (UPTECH) cross-sectional study was conducted in 8-11-year-old schoolchildren attending 25 primary (elementary) schools, randomly selected from the Brisbane Metropolitan Area, Queensland, Australia. Main study findings outlined indirect evidence of distal airway deposition (raised C reactive protein) but as yet, there is no direct evidence in the literature of effects of UFP exposure on peripheral airway function. We present further UPTECH study data from two sensitive peripheral airway function tests, Oscillometry and Multiple Breath Nitrogen Washout (MBNW), performed in 577 and 627 children (88% and 96% of UPTECH study cohort) respectively: mean(SD) age 10.1(0.9) years, 46% male, with 50% atopy and 14% current asthma. Bayesian generalised linear mixed effects regression models were used to estimate the effect of UFP particle number count (PNC) exposure on key oscillometry (airway resistance, (Rrs), and reactance, (Xrs)) and MBNW (lung clearance index, (LCI) and functional residual capacity, (FRC)) indices. We adjusted for age, sex, and height, and potential confounders including socio-economic disadvantage, PM2.5 and NO2 exposure. All models contained an interaction term between UFP PNC exposure and atopy, allowing estimation of the effect of exposure on non-atopic and atopic students. Increasing UFP PNC was associated with greater lung stiffness as evidenced by a decrease in Xrs [mean (95% credible interval) -1.63 (-3.36 to -0.05)%] per 1000#.cm-3]. It was also associated with greater lung stiffness (decrease in Xrs) in atopic subjects across all models [mean change ranging from -2.06 to -2.40% per 1000#.cm-3]. A paradoxical positive effect was observed for Rrs across all models [mean change ranging from -1.55 to -1.70% per 1000#.cm-3] (decreases in Rrs indicating an increase in airway calibre), which was present for both atopic and non-atopic subjects. No effects on MBNW indices were observed. In conclusion, a modest detrimental effect of UFP on peripheral airway function among atopic subjects, as assessed by respiratory system reactance, was observed extending the main UPTECH study findings which reported a positive association with a biomarker for systemic inflammation, C-reactive protein (CRP). Further studies are warranted to explore the pathophysiological mechanisms underlying increased respiratory stiffness, and whether it persists through to adolescence and adulthood.

Indoor and outdoor nitrogen dioxide concentration in residential houses in Australia

Abstract: As part of a larger indoor environmental study, residential indoor and outdoor levels of nitrogen dioxide (NO2) were measured for 14 houses in a suburb of Brisbane, Queensland, Australia. Passive samplers were used for 48-h sampling periods during the winter of 1999. The average indoor and outdoor NO2 levels were 13.8 ± 6.3 and 16.7 ± 4.2 ppb, respectively. The indoor/outdoor NO2 concentration ratio ranged from 0.4 to 2.3, with a median value of 0.82. The results of statistic analyses indicated that there was no significant correlation between indoor and outdoor NO2 concentrations, or between indoor and fixed site NO2 monitoring station concentrations. However, there was a significant correlation between outdoor and fixed site NO2 monitoring station concentrations. There was also a significant correlation between indoor NO2 concentration and indoor submicrometre (0.007–0.808 μm) aerosol particle number concentrations. The results in this study indicated indoor NO2 levels are significantly affected by indoor NO2 sources, such as a gas stove and cigarette smoking. It implies that the outdoor or fixed site monitoring concentration alone is a poor predictor of indoor NO2 concentration.